Joe Biden expanded the president's power to block foreign mergers with U.S. companies. Donald Trump used that opening to give himself unprecedented control.

Together, Nippon Steel and U.S. Steel will be a world-leading steelmaker, with best-in-class technologies and manufacturing capabilities,” the companies said.

Nippon Steel offered Washington a "golden share," which gives the government oversight over some decisions, to get approval for its takeover of U.S. Steel.

Nippon Steel seals a $14.9 billion acquisition of US Steel, marking a major shift in the global steel industry and ...